<script>
import {onMounted, ref} from 'vue'
import {watch} from 'vue'

export default {
  name: 'XtxCarousel',
  props: {
    sliders: {
      type: Array,
      default: () => []
    },
    // 轮播图时间间隔5s
    duration: {
      type: Number,
      default: 5000
    },
    autoPlay: {
      type: Boolean,
      default: true
    }
  },
  setup(props) {
    // 图片索引
    const index = ref(0)
    let timer = null
    const autoPlayFn = () => {
      clearInterval(timer)
      timer = setInterval(() => {
        index.value++
        // 如果播到最后一张，重新开始
        if (index.value === props.sliders.length) {
          index.value = 0
        }
      }, props.duration)
    }

    const stop = () => {
      if (timer) clearInterval(timer)
    }

    const start = () => {
      if (props.sliders.length && props.autoPlay) autoPlayFn()
    }

    // 指示器切換上下張
    const toggle = (step) => {
      const newIndex = index.value + step
      // 最后一张往后是第一张
      if (newIndex >= props.sliders.length) {
        index.value = 0
        return
      }
      // 第一张往前是最后一张
      if (newIndex < 0) {
        index.value = props.sliders.length - 1
        return
      }
      index.value = newIndex
    }

    // sliders中有数据才自动播放
    watch(() => props.sliders, (newVal) => {
      if (newVal.length && props.autoPlay) {
        index.value = 0
        autoPlayFn()
      }
    }, {immediate: true})

    onMounted(() => {
      clearInterval(timer)
    })


    return {
      index,
      start,
      stop,
      toggle,
    }
  }
}
</script>


<template>
  <!-- 轮播图 -->
  <div class='xtx-carousel' @mouseenter="stop()" @mouseleave="start()">
    <ul class="carousel-body">
      <li :class="{fade:index===i}" class="carousel-item" v-for="(item, i) in sliders" :key="i">
        <router-link :to="item.hrefUrl" v-if="item.hrefUrl">
          <img :src="item.imgUrl" alt="">
        </router-link>
        <div class="slider" v-else>
          <router-link v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{ goods.name }}</p>
            <p class="price">&yen;{{ goods.price }}</p>
          </router-link>
        </div>
      </li>
    </ul>
    <a @click="toggle(-1)" href="javascript:" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
    <a @click="toggle(1)" href="javascript:" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
    <div class="carousel-indicator">
      <span @click="index = i" v-for="(item, i) in sliders" :key="i" :class="{ active: index === i }"></span>
    </div>
  </div>
</template>


<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;

  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }

    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;

      &.fade {
        opacity: 1;
        z-index: 1;
      }

      img {
        width: 100%;
        height: 100%;
      }
    }

    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;

      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        transition: background-color 0.2s;

        ~ span {
          margin-left: 12px;
        }

        &.active {
          background: #fff;
        }
        &:hover {
          background-color: palegreen;
        }
      }
    }

    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, .2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;

      &.prev {
        left: 22%;

        &:hover {
          background-color: #1dc779;
        }
      }

      &.next {
        right: 20px;
        &:hover {
          background-color: #1dc779;
        }
      }
    }
  }

  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}

.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;

  > a {
    width: 240px;
    text-align: center;

    img {
      padding: 20px;
      width: 230px !important;
      height: 230px !important;
    }

    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }

    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>